The massive light source on the left takes too much away from the focal point. It's almost blinding compared to the rest of the picture. I would suggest toning it down a bit, and making the whole piece in general a bit darker.

I would also lower the gradient map/filters you have on aswell, because they overpower everything.

Another thing that I'd suggest is leaving text out for awhile until you get the hang of it, and you truly understand what makes a good tag/signature. Then focus on working on the text.

Considering it's your first signature, you did a nice job at covering the fact it's indeed a number of messy brushes put together.

Aside that, which is fine as it's your first "thought" signature, there are a lot of things to improve.

Firstly, as it has already been said, the huge light on the left is way too bright, it has to be toned down.
Additionally, if you notice there's a bright circle around said light, you can see it's really noisy. That was caused by the type of layer you chose for the effect.
Many brushes are blurred, while many other are completely sharp and have a different style. Also, for whatever reason, the yellow-green blur in the right side of the image is visibly pixelated.

My suggestion to improve is to keep it simple.
Your signature looks alot like my first ones: brushes spammed all around, filters on top of filters, random lights, random filters applied,etc.
When you're just starting out, it's important to be neat with your works.

So, what i suggest you to do is to pick any render of your liking, resize and carefully place your render.
Now, pick an array of colors between two and five, if possible taken from the render itself (in this case, it'd been green-ish grey, bright yellow and orange).
Then forget you have c4ds and only focus on yourself, the render and the brushes. Try to create layers that look neat and make sure they "interact" with the render as that's why you use a render in the first place!
If you ever feel like the only way of proceeding is by adding more and more brushes or resorting to filters/c4ds, then take a step back as that's the wrong way.

By the way, the best thing in the signature is probably the text placement: it looks really sweet.